The four Swiss airports that serve the bulk of the annual World Economic Forum’s business jet traffic could see a nearly 15 percent increase in aircraft movements, said global charter provider Air Charter Service. Movements at the four-day event that begins tomorrow in Davos, Switzerland, could reach almost 1,500, ACS predicted, up from more than 1,300 last year.

Andy Christie, ACS’s private jets director, said working with WingX the companies looked at private jet activity over six days—including the day before WEF and the day after—at the airports that primarily serve the forum’s attendees: Zürich, Dübendorf, St. Gallen-Altenrhein, and St. Moritz. WingX and ACS looked at the data going back to 2013 to make their prediction for 2019.

Countries with the most arrivals and departures over the past five years are Germany, France, the UK, U.S., Russia, and UAE, respectively. Christie said there is a trend toward heavy jets, with Gulfstream GVs and Bombardier Global Expresses both being used more than 100 times each in 2018. “This is at least in part due to some of the long distances traveled, but also possibly due to business rivals not wanting to be seen to be outdone by one another,” he said.